This application relates generally to gas turbine engine rotor assemblies, and more particularly, to bearing assemblies used with gas turbine engine rotor assemblies.
Gas turbine engines typically include a fan rotor assembly, a compressor, and a turbine. The turbine includes an array of rotor blades extending radially outward from rotor disk that is coupled to a rotor shaft. The rotor shaft transfers power and rotary motion from the turbine to the compressor, and is supported longitudinally through a plurality of roller bearing assemblies and axially through at least one thrust bearing assembly. Known roller bearing assemblies include rolling elements supported within a paired race.
During operation, failure of a bearing assembly may result in an In Flight Shut Down (IFSD), and/or an Unscheduled Engine Removal (UER). At least one known gas turbine engine includes a magnetic chip detection system that includes a magnet that attracts metal shavings created during bearing contact fatigue failures such as, but not limited to micro-spalling, peeling, skidding, indentations, and/or smearing. More specifically, magnetic chip detectors facilitate identifying the presence and the quantities of metallic chips in a gas turbine lube oil scavenge line. In addition, a scanning electron microscope (SEM) may be used to determine the source of the metal shavings. However, known magnetic chip detection systems and SEM analysis systems can only detect a bearing spalling that has already occurred.
At least one known gas turbine engine also includes a vibration measurement system that transmits relatively high frequency acoustic emissions through the bearing to verify a bearing failure caused by bearing contact fatigue has occurred. However, known vibration measurement systems may not be able to successfully identify the bearing failure if the transmitted signal is degraded when passed through a lubricant film that is used to lubricate the bearing. Accordingly, identifying the bearing component frequencies among a plurality of engine operating frequencies may be relatively difficult. Accordingly, known systems are generally not effective in detecting initial bearing flaws and/or defects that may result in bearing spalling, in monitoring bearing damage and/or spall propagation, or in assessing the overall bearing damage including multi-spall initiations and progression.